@arnix said in Suggestion for servo motor --> big delta robot:
Sorry for late reply.
To better understand my situation, am sending latest videos. One is with slower and second is on top speed.
Its without up/down movement, just positioning and extruder should position itself on X0 Y0 ( at higher speed it misses cca 10 cm ).
1.) https://ufile.io/u2cim ( just click, free slow download / open or save ).
@691175002 and @jrjones88
I think that the problem is in the gearing and lack of encoder. The material that am using at the moment aluminum but pipe wall is 2mm and pipe diameter is 2 centimeters so there should not be any problems, IMHO. As you guys point it out, 10:1 gearbox that am using could be the main problem because it has backlash of 3 degrees which is a lot, at no load. This is the stepper motor that am using :
High ratio belt reducer - DIY :
- i can do that, can you guys suggest some optimal ratio and motor ?
- what kind of setup would you suggest ( power supply, controller, etc. ) that can be controlled by duet ?
Yes your backlash is the issue right now. For the optimal ration and motor, that is a compromise between speed and holding power. Since you have a 1.89 Nm geared to 10:1 right now and it is too slow (you said cycle time is 1.5 seconds, desired is 1 second), your gearing needs to be a smaller ratio, say 8:1 or 5:1.
A belt reduction is a good way to reduce backlash, but depends on how much room you have. If you goto a 5:1 ratio, you might need a new motor as well, since your output torque is reduced by half on your current motor.
I don't know what your budget is (is this hobby or work/school?). If it isn't hobby I would look at Oriental Motors, they have good motors (all kinds) and drives (that accept pulsed input). But you are looking at around $500-1000 per motor/drive combination.
For example, this motor is has 0.05° backlash. https://catalog.orientalmotor.com/item/az-series-absolute-encoder-stepper-motors/az-series-85-mm-absolute-encoder-stepper-motors-dc/azm98ac-hp15
And once you reduce your backlash, I would still look at stiffening your frame (cross braces are easy to add in your case). Take a look here: https://youtu.be/p1Lrz0gPvOA
The frame is very beefy compared to the robot. This video also has some good views on the arms (very similar to the current Delta printers, but then again, delta pick and place robots have been around longer than delta 3d printers)